Method of treating hydrocarbons



W. F. RITTMAN.

METHOD OF TREATING HYDROCARBON&

APPUCATION FRED AUG.3.I9I7. RENEWED FEB.1,1922

1,41 9, 1 25; Pa nte J 11116 6, 1922.

CONDENSER Rem/7kg F 62- 507M905 I file/W05 Hmnaanmsmv F'ED WALTER F. RIT'EM AN, 0F PITTSBURGH, PENNSYLVANIA, ASSIG-NOR T0 SYNTHETIG HYIYRJQCARBON COMPANY, OF PITTSBURGH, PENNSYLVANIA, A. CORPGRATION OI? DELAWARE.

METHOD OF TREATING HYDROCARBONS.

intense.

Application filed August 3, 1917, Serial No. 184,231. Renewed February 1, 1922. Serial No. 533508.

To all whom it may concern:

Be it known that I WALTER E. RITTMAN, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, a citizen of the United States, have invented or dis covered certain new and useful "improvements in Methods of Treating Hydrocarbons, of which improvement the following is a specification.

In the production of lower boiling hydrocarbons from higher boiling hydrocarbons, it has been found possible, and often desirable to treat different kinds by different methods. This invention has for its primary object the cracking of hydrocarbons boiling below 600 degrees F, but'not suitable for motor fuel in their original condition. In cracking operations where liquid oil is cracked in contact with cracked vapors, the process is limited to treating high boiling oils such as those having a boiling point above that of oils best suited for this present invention.

In the present invention, the liquid oil is fed into the lower portion of a substantially vertical tube, and the oil is vaporized through the application of heat to an upper oil into the desired disc or section of oil. The vapor resulting from the vaporization of this disc, passes upward in the retort and is subjected to a higher temperature sufficient to crack the roducts. Further, heat employed for heating thevaporizing and cracking portions of the retort is derived from the same source i: e., a common source of heat for all operations. The means of changing the oil into vapors, preparatory to the principal cracking in the vapor phase, constitute an important part of this invention.

In the practice of this invention, relatively small amounts of liquid oil is subjected successively to the high temperature, thereby avoiding the dangers incident to the cracking of oils in stills. etc. Further, it will be seen that the practice of this invention does not cause continued selective and continually different or changing compositions of vapors being cracked, and thereby necessitates constant adjustment of conditions for cracking, but after a short period the vapors above the surface of the oil are of a uniform composition as contrasted with selective distillasurface of the liquid body. This phenomenon, wh ch is a novel and an important part of this lnvention, will be made clear by assuming that the liquidbeing fed in consists of but two hydrocarbons; the first (a) boilin at 450 degrees F and the second (6) boiling at 500 degrees F. In the ordinary distillation process, or any process where heat is applied at points other than the surface, thus promoting circulation, there is a natural tendency for the a hydrocarbons to distill ofi, leaving a preponderance of b hydrocarbons. In the present invention, however, the small portions at the upper end of the liquid column are brought successively into above the boiling temperature of both a and 5 molecules in the retort. F or a very short tlme at the beginning of the operation, the natural tendency prevails, i. e., a preponderance of a molecules leaves the surface as vapor, leaving a preponderance of '6 molecules in the liquid. However, with a given rate of feed, the level of the 6 molecules rises in'the retort, and comes in contact with a more highly heated and increasing vaporizing area with the very natural result that in a short time the ratio of 7) molecules passing oil is e ual to the ratio of I) molecules in the liquid being fed, even though the same are not from the same particular fraction of oil. Were this not the case, the I) molecules would so accumulate. in the substantially vertical retort that the same would become'filled with liquid, leaving no space above for the vapor-phase cracking, and the process would be inoperative. Since the level of the liquid will be uniformly maintained in commercial operation, there will be a passing off of a continued uniform mixture from the surface of the oil. It is believed that after the treatment has become established, 1) molecules will be given off from the upper and most highly heated portion of the li uid column, while a molecules will be given off from the next adjacent but less highly heated portionof the column and that vapors derived from these sources will mingle'above the liquid column and hence there will be a uniform mixture of vapor passing into the cracking zone.

The process herein described does not work .to the same advantage with high boiling oils,

such as a 34 or 36 degree Baum gas 011, be-' ortions of the retort heated Patented June 663, 1%22. a

Walls of the retort atthe vaporizing surface.

accumulate carbon and other objectionable carbonaceous matter, thereby interfering with continuous operation, or necessitating special mechanical means for removing the carbon deposits as formed. In working with the light oils, however, this trouble is not serious since the boiling points ofv the initial constituents are relatively low. Further, if it should be found desirable to use distillates which deposit sufficient carbon to interfere with continuous operation, mechanical means may be provided in the form of scrapers to continuously or periodically scrape,or otherwise clean-the walls of the retort. In addition, when such ,distillates are used, the mechanical action just referred to may be displaced or supplemented by periodically drawing off all of the liquid oil in the retort A, thereby carrying ofi any carbon particles which may have fallen from the walls of the retort.

The amount of vapors generated will vary with (the cross sectional area of the retort being disregarded) the temperature of the retort and the depth of the disc of liquid i downward due to its higher specific gravity.

In the accompanying drawings forming a part of this specification, Fig. 1 is a diagrammatic view showing the form of apparatus adapted to the practice of the method described herein, and Fig. 2 is a similar view illustrating a modification of apparatus. y

' The invention is not limited to the use of a retort discharging at its upper end, as shown in Fig. 1. For instance, a vertical pipe 3 with an opening at its upper end and. having its lower end connected to a segregating tank 4, may be passed up into retort A. In this case, the vapors to be cracked would pass upward in the retort and enter ing the upper portion of the inner pipe 3, pass downward therethrough to the segregating tank, said pipe being extended through the liquid body in the retort. In

this form, it is evident that'the oil vapors will be subjected to a cracking temperature for a longer period, in that their temperature is maintained not only during their passage through the retort, but down througha portion of the pipe 3 as well. In this form, the vapors passing down through the pipe 3 will give up heat toithe liquid in the retort and thereby assist the heatingof the liquid in the retort. This transfer ofheat has the-further advantage of assisting,

in the condensation of the vapors flowing down through the pipe 3. In this practice,

'the oil is heated in the form of an annulus rather than a disc. Although the vaporspassing down through the pipe 3 give up some heat through their entire passage through the oil in the retort, it is evident that the greatest heat from thevapors in the pipe 3 would be given'to the, upper portion of the oil in the retort, and that the amount of heat given from the walls of the pipe to the, liquid body in the retort would become progressively less, and an important principle used in this invention; (i. e., maintaining the hottest liquid above less hot or colder liquid) would be unaltered, and at the same time, there would be a heat economy effected in'that the cracked vapors would impart their heat to the liquid about to be vaporized and cracked.

As shown herein, the retort A is, in the practice of the invention, adapted to be heated in any suitable form or construction of furnace indicated at 5. The hydrocarbon to be treated is fed into the lower end of the retort through a pipe 6 and in the form shown in Fig. l, the vapors, gases, etc., flow through to pipe 7 to a segregating chamber, as a condenser, indicated at 8. In the form shown in Fig. 2, the vapors, gases, etc., flow from the upper portion of the retort down through apipe 3 having its lower end connected to a segregating chamber 4. In order .to permit of the removal of material from the retort, the latter is provided with a discharge pipe 9 at its lower end.

I claim herein as my invention:

1. The method herein described for treat-- ing hydrocarbons which consists in applying a vaporizing heat to the portions of a body of liquid oil at and adjacent to theupper surface thereof, other portions of the liquid being at a lower temperature, subjecting the vapors arising from such heated portions to a cracking temperature, and segregating the vproducts resulting from such treatment.

. 2. The method herein described for treating hydrocarbons, which" consists in feeding liquid oil into the lower portions of a vertical retort, applying a vaporizing heat to the oil in the retort in such manner as to avoid circulation of the liquid oil due to differences of temperature in the oil, subjectingthe'vapors arising from the heatd portions of the oil to a cracking temperature and segregating the products resulting from such treatment.

'3. The method herein described for treating hydrocarbons, which consists in feeding oil into the lower portion of a vertical re tort, applying a vaporizing heat to the portions of the oil in the retort at and adjacent emma to'the surface thereof, causing the vapors thus formed to pass successively in opposite directions through a one heated to a cracking temperature, discharging the cracked vapors, downwardly, through the conduit passing through the body of oil in the .retort, and segregating the products resulting from such treatment.

4, The method herein described for treating hydrocarbons consists in feeding liquid oil into the lower portion of a vertical retort, applying a vaporizing heat to the portion of the oil in the retort in such manner as to avoid circulation of the liquid oil due to difierences oftemperature in the oil, subjecting the vapors rising from the heated portions of the oil to a cracking tempera ture and pressure, for such a period of time as required for the production of the desired hydrocarbon end product.

5. The method herein described for treating hydrocarbons which consists in applying such a heatto the portionsof liquid oil in a retort at or adjacent to the surface 'thereof as will efiect a vaporization and cracking of the liquid, subjecting the vapors thus formed to a craekin temperature and pressure, for a period of time adapted'to the production of the desired hydrocarbon end product.

In testimony whereof, I have hereunto set my hand.

WALTER F. RITTMAN.' 

